  SEQ CHAPTER \h \r 1 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF                  

PREVENTION, PESTICIDES AND 

TOXIC SUBSTANCES        

MEMORANDUM

DATE:		November 10, 2008

SUBJECT:	Transmission of Background and Reference Materials and Charge
to the Panel for the December 2-5, 2008 Session of the FIFRA Scientific
Advisory Panel (SAP) Entitled “Scientific Issues Associated with
Worker Reentry Exposure Assessment”

FROM:		Tina Levine

				Division Director

				Health Effects Division

		

TO:		Sharlene Matten

		Designated Federal Official

		FIFRA Scientific Advisory Panel

				Office of Science Coordination and Policy (7201M)

The December 2-5, 2008 session of the Federal Insecticide Fungicide
Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) will discuss
issues related to the exposure assessment of reentry workers following
pesticide applications in agricultural settings, also known as
post-application farmworker exposure assessment.  At this meeting, the
Agency is seeking review, comment, and guidance from the Panel on three
issues related to the Agency’s post-application farmworker exposure
assessment methods.  These issues include:

Identification of reentry activities for the purposes of
post-application farmworker exposure assessment;

Grouping of similar reentry activities for post-application farmworker
exposure assessment purposes, including those considered no/low contact
activities where minimal exposure is expected; and,

Evaluation of workday duration in post-application farmworker exposure
assessment.

 

The remainder of this memorandum provides a detailed list of background
and key reference materials, which are outlined in Tables 1 and 2, and
the specific charge to the Panel.  These materials do not contain any
information protected under statute as Confidential Business Information
(CBI), nor do they contain any materials protected by copyright.  These
materials do contain information protected from disclosure to foreign
and multi-national pesticide producers under FIFRA Section 10(g).

Background and Reference Materials

Table 1:  December 2-5, 2008 FIFRA SAP Background Materials

Background Document	File Name	Author	Indicate Whether FIFRA 10(g) or ©
Protected

Scientific Issues Associated with Worker Reentry Exposure Assessment
U.S. EPA (2008)_FIFRA SAP_Worker Reentry.pdf	EPA

	Exhibit A	Exhibit A_TC Calculation Example_ARF024.xls	EPA

	Exhibit B	Exhibit B_TC Calculation Example_ARF024.pdf	EPA	10(g)

Exhibit C	Exhibit C_Crop-Activity Combinations.xls	EPA

	Exhibit D	Exhibit D_ARTF TC Data Summary.xls	EPA

	Exhibit E	Exhibit E_ARTF Grower Survey_Workday Duration Summary.xls	EPA

	Exhibit F	Exhibit F_TC Cluster OH_Mixed-Model Analysis.doc	EPA



Exhibit_F_TC_Case_Study.sas7bdat	EPA

	Development of the ARTF Transfer Coefficient Database	Bruce and
Korpalski (2008) Development of ARTF TC Database.pdf	ARTF

	

Table 2:  December 2-5, 2008 FIFRA SAP Reference Materials

Reference Document	File Name	Indicate Whether FIFRA 10(g) or ©
Protected

ARTF (1996). Agricultural Reentry Activities and Pesticide Exposures In
The United States and Canada:  Results of Crop Production Experts. Doane
Marketing Research, Inc.	ARTF (1996)_ARTF Expert Survey.pdf	10(g)

	ARTF (1996)_ARTF Expert Survey_List of Experts.pdf

	ARTF (1996), Determination of Dermal and Inhalation Exposure to Reentry
Workers During <Activity> in <Crop>, A generic protocol for conduct of
post-application exposure studies	ARTF (1996)_Generic Reentry
Protocol.pdf	10(g)

ARTF, Use of Generic TCs to Evaluate Worker Safety – A Brief Summary
of the Approach, Provided by ARTF, LLC., March, 2008	ARTF (2008)_Use of
Generic TCs.pdf

	Baugher, D.G. (2006), Penetration of Clothing by Dislodgeable Foliar
Residues of Pesticides during Agricultural Occupational Reentry, ARTF,
LLC; February 22, 2006.  (MRID 46789302)	Baugher, D.G. (2006)_Clothing
Penetration.pdf	10(g)

Bruce, E. and Artz, S. (2001), Technical Issues and Procedures for
Handling Data from Agricultural Reentry Studies Purchased by ARTF, ARTF,
LLC; August 28, 2001.  (MRID 45491905)	Bruce, E. and Artz, S.
(2001)_TechIssues ARTF Purchased Data.pdf	10(g)

Bruce, E. (2002), Evaluation of Dislodgeable Foliar Residue Techniques,
Statistical Distributions, and Initial Residues, ARTF Study No. ARF054,
January, 2002.  (MRID 45574001)	Bruce, E. (2002)_DFR
Technique-Distribution-Initial Residues.pdf	10(g)

Bruce, E., Holden, L. and Korpalski, S. (2003). Transfer Coefficient:  A
Generic Tool for Estimating Pesticide Exposure to Agricultural Workers
Who Re-Enter Treated Crops, ARTF LLC; June 27, 2003.  (MRID 46040301)
Bruce, E., et al (2003)_Genericness Report.pdf	10(g)

Bruce, E., Holden, L. and Korpalski, S., (2006). Reissued Report:
Agricultural Reentry Task Force Transfer Coefficient Database: A Summary
of its Development and Use, ARTF LLC, January 13, 2006.  (MRID 46734002)
Bruce, E., et al (2006)_REISSUE_ARTF TC Database Report.pdf	10(g)

	Bruce, E., et al (2003)_ARTF TC Database Report.pdf	10(g)

Nigg, H.N., et al (1984).  The Development and Use of a Universal Model
to Predict Tree Crop Harvester Pesticide Exposure.  Journal of the
American Industrial Hygiene Association 45:  182-186.	Nigg, H.N.
(1984)_Model Predict Harv Exp.pdf

	PMRA & U.S. EPA. (1997). Workshop On Post-application Exposure
Assessment – Final Report.	PMRA & U.S.EPA (1997) Joint PMRA EPA
Workshop On Postapplication Exposure Assessment.pdf

	Popendorf, W (1980).  Exploring Citrus Harvesters’ Exposure to
Pesticide Contaminated Foliar Dust, Am. Industr. Hygiene Assoc. J.
41:652-659.	Popendorf, W (1980)_Exploring Citrus Harvesters.pdf

	Ross, J. (2001). Peer Review Summary Report and ARTF Response to Peer
Review Comments, ARTF Peer Review Panel, August, 2001.  (MRID 45491903)
Ross, J. (2001)_Peer Review Report.pdf	10(g)

Ross, J., Driver, J., Lunchick, C., Wible, C., and Selman, F. (2006). 
Pesticide Exposure Monitoring Databases in Applied Risk Analysis.  Arch.
Envir. Contam. Tox., v. 186, pp. 107-132	Ross, J., et al
(2006)_Pesticide Exposure Monitoring D-Bases.pdf

	Thompson, R. (1998). Agricultural Worker Crop Contact from Reentry
Activities Performed in the USA and Canada: Grower Results, Doane
Marketing Research, Inc., MRID 44802601	Thompson, R., (1998)_ARTF Grower
Survey.pdf	10(g)

	Korpalski, S., and Bruce, E., (2000)_ADDENDUM_ARTF Grower Survey.pdf
10(g)

U.S. EPA (1980). Minutes of FIFRA SAP Subcommittee Meeting (February
21/22, 1980) Signed by Assistant Executive Anthony Inglis.	U.S.EPA
(1980)_FIFRA SAP Subcommittee Review.pdf

	U.S. EPA (1981). Informal Review of Draft Proposed Pesticide
Registration Guidelines, Subpart K:  Exposure Data Requirements: Reentry
Protection (May 13/14, 1981), Signed by Executive Secretary Philip H.
Gray, Jr.	U.S.EPA (1981)_FIFRA SAP Informal Review.pdf

	U.S. EPA (1984).  Pesticide Assessment Guidelines, Subdivision K –
Exposure: Reentry Protection [NTIS Document Number PB85-120962]  
U.S.EPA (1984 & 1986a)_SubdivisionsU&K.pdf

	U.S.EPA (1986a). Pesticide Assessment Guidelines, Subdivision U –
Applicator Exposure Monitoring [NTIS Document Number PB87-133286
(October, 1986)]



U.S. EPA (1986b). Transmittal of the Final FIFRA Science Advisory Panel
(SAP) Reports on the February 11-12, 1986 Meeting	U.S. EPA (1986b)_
FIFRA SAP Minutes.pdf

	U.S. EPA (1989). Good Laboratory Practices (40CFR160)	U.S.EPA
(1989)_GLPs40CFR160.htm

	U.S. EPA (1994). Breakout Summary Report For Workshop On The Revisions
To Subdivision K Post-Application Exposure Guidelines (April 14-15,
1994)	U.S.EPA (1994)_WorkshopSummary.pdf

	U.S. EPA (1995). Data Call-In Notice For Post-Application Exposure Data
U.S.EPA (1995)_ReentryDataCall-In.pdf

	U.S. EPA (2000). Science Advisory Council For Exposure Policy 3.1,
Agricultural Transfer Coefficients (Original 5/7/98 revised 8/7/2000)
U.S. EPA (2000)_Policy003.1.AgriculturalTransferCoefficients.pdf

	U.S. EPA, (1993). Pesticide Rejection Rate Analysis: Occupational and
Residential Exposure:  [EPA Document 738-R-93-008]	U.S.EPA
(2003)_RejectionRateAnalysis.pdf

	

Charge to the Panel

TOPIC A:  Crop-Activity Grouping/Clustering

In 1995, the Agency issued a data call-in (DCI) notice requiring the
development of information on the exposure potential associated with
labor activities in agriculture which occur in previously treated areas
(e.g., harvesting).  The central premise in the development and
collection of such exposure monitoring data is that activities which
exhibit similar magnitudes and patterns of exposure can be grouped
together for exposure assessment purposes.  It would also follow that
crop-activity combinations not actually monitored, but that were similar
from both ergonomic and agronomic perspectives, can be represented by
those that were monitored.  Based on this premise, the Agency has
identified several key factors for consideration by the Panel.  They
include the identification of labor activities in agriculture,
evaluation of the possible grouping approaches for similar crop-activity
combinations, and categorization of certain activities as no/low contact
in the Agency’s Worker Protection Standard (40CFR170).  Specifically,
the Agency identified the following issues for the Panel to consider:

Please comment on the strengths and limitations of the approaches and
data sources used to identify the universe of hand labor activities for
exposure assessment purposes.  Please identify any activities that EPA
has not listed for the crops included in the scope of the DCI.

The ARTF has recommended various crop-activities be grouped together or
clustered for the purposes of estimating exposure and has proposed and
conducted or purchased one or more exposure monitoring studies to be
used to represent each cluster.  The regulatory agencies also agree with
the concept of clustering like crop-activity combinations for this
purpose.  Please comment on the following:

The methods used by ARTF for the purposes of creating clusters for
exposure assessment purposes.

Statistical, agronomic, or other support for or against (1) the
ARTF-proposed clusters; (2) the Agency evaluation of the ARTF-proposed
clusters, and (3) the Agency-suggested alternative cluster schemes
outlined below.  Please include the rationale and reasoning for any
Panel-recommended changes or modifications.  The SAP Review Code in the
list refers to Table 3 below, which provides a summary of the ARTF
clusters, the Agency-suggested alternatives, and relevant page numbers
in the Agency’s background document.  

Hairy Leaf Field Crops (clusters HH, HHt, and HS) [SAP Review Code A]

Smooth-leaf Field Crops (clusters SH, SSR, SSS, SW and Sx) [SAP Review
Code B]

Waxy-leaf Field Crops (clusters WIH, WIS, and Wm) [SAP Review Code C]

Orchard Crops

Cluster OH and the Agency suggestion for a separate cluster for thinning
[SAP Review Code D-1]

Clusters OHn and OW crop [SAP Review Codes D-2 and D-4]

Cluster OP [SAP Review Code E-3]

Trellis Crops

Cluster THb [SAP Review Code E-1]

Cluster THg and the Agency suggestions to further separate into clusters
for hand harvesting wine grapes (THwg) and table/raisin grapes (THtg) as
well as utilizing the hand harvesting table/raisin grape cluster to
represent girdling [SAP Review Code E-2]

Cluster TP and the Agency suggestion to group with cluster OP (as shown
in Figure 31 of the Agency’s background document) [SAP Review Code
E-3]

Cluster Tx [SAP Review Code E-4]

Greenhouse and Nursery Crops

Clusters GHf and GHv [SAP Review Code F-1]

Cluster GN and the Agency suggestion to have an additional cluster for 
hand-harvesting nursery crops (GHn) [SAP Review Code F-2]

Crop Irrigation (cluster I) [SAP Review Code G]

Mechanical Harvesting Cotton (clusters CHp, CHm, and CHt) [SAP Review
Code H]

Turf (clusters DH and DM) [SAP Review Code I]



Table 3:  Reference Table for Charge Question 2 (b)

ARTF Study	ARTF Proposal	Agency Proposal	SAP Review Code	Page No.

Category/ Study Code	Crop	Activity	Cluster Code	Description	Summary of
Agency Review of ARTF Proposal	Cluster Code



Hairy-leaf, Field Crop Clusters

ARF045	Cucumbers	Hand Harvesting	HH	Hairy-leaf field crops:  hand
harvesting and similar contact activities	The Agency concurs with ARTF's
proposal	HH	A	54-59

ARF049	Summer Squash	Hand Harvesting







ARF024	Tobacco	Hand harvesting	HHt	Hairy-leaf (Tobacco):  hand
harvesting and canopy management	The Agency concurs with ARTF's proposal
HHt



ARF022	Sunflowers	Scouting	HS	Hairy-leaf field crops:  scouting and
similar contact activities	The Agency concurs with ARTF's proposal	HS



Smooth-leaf, Field Crop Clusters

ARF051	Tomato	Tying	SH	Smooth-leaf field crops:  hand harvesting and
tying	The Agency concurs with ARTF's proposal	SH	B	50-54

AR1001	Strawberry	Hand Harvesting







AR1023	Tomato	Hand Harvesting







AR1024	Strawberry	Hand Harvesting







AR1025	Cotton	Scouting	SSr	Smooth-leaf field crops:  scouting in row
conditions	The Agency concurs with ARTF's proposal	SSr



AR1027	Tomato	Scouting







ARF009	Corn	Scouting	SSs	Smooth-leaf field crops:  scouting in solid
stand conditions	The Agency concurs with ARTF's proposal	SSs



ARF021	Dry Pea	Scouting







AR1006	Cotton	Hand weeding	SW	Smooth-leaf field crops:  hand weeding,
thinning, and similar contact activities	The Agency concurs with ARTF's
proposal	SW



AR1018	Cotton	Hand weeding







AR1019	Dry Pea	Hand weeding







ARF010	Sweet Corn	Hand harvesting	Sx	Smooth-leaf field crops:  intense
contact activities	The Agency concurs with ARTF's proposal	Sx



Waxy-leaf, Field Crop Clusters

ARF050	Cabbage	Hand harvesting	WIH	Waxy-leaf field crops, low height: 
hand harvesting and similar contact activities	The Agency concurs with
ARTF's proposal	WIH	C	59-61

AR1008	Cauliflower	Scouting	WIS 	Waxy-leaf field crops, low height: 
scouting and similar contact activities	The Agency concurs with ARTF's
proposal	WIS 



ARF011	Cauliflower	Scouting	Wm	Waxy-leaf field crops, medium height: 
all activities, plus full foliage weeding	The Agency concurs with ARTF's
proposal	Wm



ARF012	Cauliflower	Hand harvesting







ARF037	Cabbage	Hand weeding







Orchard Crop Clusters

ARF025	Apples	Hand Harvesting	OH	Orchard crops:  hand harvesting and
similar contact activities	The Agency generally concurs with ARTF's
proposal.  However, one potential alteration to the proposed crop
grouping could be an additional cluster for orchard crop thinning.  The
Agency believes this activity may be more contact-intensive and
therefore could be considered separately in exposure assessments.
Possibly create a separate cluster for orchard crop thinning	D-1	63-69

ARF028	Oranges 	Hand Harvesting







ARF041	Oranges 	Hand Harvesting







ARF042	Grapefruit	Hand Harvesting







AR1002	Peaches	Hand Harvesting







AR1003	Apples	Thinning







AR1014	Peaches	Hand Harvesting







AR1021	Peaches	Hand Harvesting







AR1016	Almonds	Mechanical Harvesting	OHn	Orchard crops:  mechanically
harvesting nuts	The Agency concurs with ARTF's proposal	OHn	D-2

	ARF033	Olives	Hand Pruning	OP	Orchard crops:  hand pruning, scouting,
and similar contact activities	See Agency review comment for ARTF
Proposal for Cluster TP	See OP/TP	See E-3

	ARF047	Apples	Hand Pruning







AR1017	Peaches	Propping	OW	Orchard crops:  hand weeding and similar
contact activities	The Agency concurs with ARTF's proposal	OW	D-4

	Trellis Crop Clusters

ARF020	Blackberries	Hand harvesting	THb	Trellis crops:  hand harvesting
caneberries and similar contact activities	The Agency concurs with
ARTF's proposal	THb	E-1	69-76

ARF048	Juice/Wine Grapes	Hand harvesting	THg	Trellis crops:  hand
harvesting grapes and similar contact activities	The Agency is
considering to further separate the THg cluster by having separate
transfer coefficients for hand harvesting wine grapes and table/raisin
grapes, respectively.  The Agency also proposes to utilize the revised
THtg cluster to represent girdling.	THwg	E-2

	AR1020	Table / Raisin Grapes	Hand harvesting



THtg



AR1022	Table / Raisin Grapes	Hand harvesting







ARF023	Table / Raisin Grapes	Scouting	TP	Trellis crops:  hand pruning,
scouting, and similar contact activities	The Agency is considering
combining similar activities conducted in trellises and orchards.  The
respective ARTF-proposed clusters OP and TP, representing activities
such as scouting and hand pruning, are very similar because shears or
other devices would be used which preclude some level of contact with
the treated plants.  Also, corresponding to Review Code E-2, girdling
would be removed from this cluster.	OP/TP	E-3

	AR1015	Table / Raisin Grapes	Cane turning	Tx	Trellis crops:  intense
contact activities	The Agency concurs with ARTF's proposal	Tx	E-4

	Greenhouse and Nursery Crop Clusters

ARF055	Solidasters, Snapdragons, Lillies	Hand Harvesting	GHf	Greenhouse
and nursery floriculture hand harvesting:  all flowers and methods	The
Agency concurs with ARTF's proposal	GHf	F-1	40-45

ARF020	Blackberries	Hand Harvesting	GHv	Greenhouse vegetables: hand
harvesting and similar contact activities	The Agency concurs with ARTF's
proposal	GHv



ARF051	Tomatoes, fresh	Tying







ARF039	Chrysanthe-mums	Pinching	GN	Greenhouse and nursery crops:  all
activities	The Agency generally concurs with ARTF's proposal.  However,
the Agency believes that there could be support for additional
separation of hand harvesting nursery crops from other nursery crop
activities.	GN	F-2

	ARF043	Nursery Stock Citrus Trees	Hand Pruning







ARF044	Nursery Stock Citrus Trees	Hand Harvesting

All crops:  transplanting

GHn



Crop Irrigation Cluster

ARF036	Potatoes	Irrigation	I	Irrigation, any crop where hand line is
possible	The Agency concurs with ARTF's proposal	I	G	78-80

Mechanical Harvesting Cotton Clusters

AR1004	Cotton	Mechanical Harvesting	CHp	Cotton, mechanical harvesting: 
picker operator and raker (based on boll residues)	The Agency concurs
with ARTF's proposal	CHp	H	61-63



	CHm	Cotton, mechanical harvesting:  module builder operator (based on
boll residues)	The Agency concurs with ARTF's proposal	CHm





	CHt	Cotton, mechanical harvesting:  tramper (based on boll residues)
The Agency concurs with ARTF's proposal	CHt



Turf Clusters

ARF035	Sod	Mechanical Harvesting	DH	Sod:  mechanical harvesting,
scouting, transplanting, and hand weeding	The Agency concurs with ARTF's
proposal	DH	I	76-78

ARF057	Golf Course Turf	Maintenance	DM	Golf courses:  maintenance
activities	The Agency concurs with ARTF's proposal	DM



As indicated in the background document, the Agency recognizes the
limitations associated with using certain statistical tests (such as the
nonparametric Wilcoxon and Kruskal-Wallis tests) to provide a broad
rationale for the separation or combination of studies to form clusters.
 Specifically, these tests do not adequately account for or consider a
number of complex features of the data such as repeated measurements on
the same worker and nesting.   Again, as stated in the text, a
mixed-model approach that incorporates the hierarchical nature of the
data is likely to be more appropriate and to more definitively address
the issues of interest regarding the degree to which specified
crop-activity combinations might be combined.  In Exhibit F, the Agency
provides a case study example of this alternate (mixed model) approach
for determining reasonable groupings of transfer coefficients (TCs) from
exposure studies involving various crop activities thought to be
ergonomically and/or agronomically similar.

The Agency believes the proposed approach illustrated in Exhibit F uses
more appropriate statistical and quantitative procedures for determining
which exposure monitoring studies can or should be combined.  Please
discuss thoughts and/or concerns with the analytical approach outlined
in Exhibit F and on the annotated SAS code provided as an attachment to
Exhibit F.  Please provide feedback on the results of the case study
which indicates that it would not be inappropriate to consider TC values
associated with hand harvesting activities in orchards to be distinct
from TC values associated with hand thinning activities in orchards (see
SAP Review Code D-1 in Table 3 above and Figure 25 in the Agency’s
background document).

Please comment on the classification of crop-activity combinations in
Agency Exhibit C, identified with a cluster code of “No TC”, as
involving no or very low exposure.  Please identify any crop-activity
combinations classified as “No TC” in Exhibit C which should be
categorized differently because of their associated exposure potential. 
Likewise, please identify any combinations which should be categorized
as “No TC” which are currently included in other clusters.  Please
explain the basis for any such recommendations.

TOPIC B:  Workday Duration

The Agency discussed its methodology for assessing post-application
exposures with an emphasis on the workday duration input.  A central
tendency value of 8 hours per day is typically used by the Agency.  The
data also show, as seen in several sources, certain portions of the
population work longer over the course of a day (e.g., 10 or 12 hours). 
However, the Agency believes that, in most cases, employing a central
tendency estimate of 8 hours per day yields an appropriately protective
estimate of risk because of the combined impact of several other inputs
in the exposure and risk assessment process.  Specifically, the
following issues have been identified for the Panel to consider:

Please comment on the strengths and limitations of the data sources used
to quantify the duration of a workday for farmworkers, as well as any
additional sources of information that could be used for the analysis of
farmworker workday duration.  If any are identified, please comment on
the possible impacts they might have on the results of the analysis
conducted by the Agency.

Please comment on the Agency’s conclusion that using 8 hours per day
for exposure assessment purposes and given the conservativeness of the
other inputs results in estimates of farmworker exposures at the high
end of the distribution of actual multi-day exposures.  To the extent
that the Panel believes that this is not the case, please suggest
alternative approaches.

Please comment on whether the Agency’s approach to single-day exposure
assessments results in farmworker exposure estimates that fall in the
high end of the distribution of actual single day exposures.  To the
extent the Panel thinks that is not the case, please suggest alternative
approaches that may generate such estimates.

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